Re: [Gumstix-users] LCD touch screen unusable on Overo/Chestnut

Hi James,
For my suggestion to change the version of Xorg, you should just be
able to opkg a different version. Here is some documentation on the
opkg command: http://gumstix.org/add-software-packages.html.
Editing the source for various packages in OE is a trickier
proposition as OE recipes use different mechanisms to fetch and build
source. For recipes that just use source code in your recipes folder,
you can simple edit and re-bitbake. Most recipes are fetched from
source control or tarballs so editing the source so it is picked up by
bitbake would mean changing something upstream. Again, there are
workarounds but it requires a knowledge of bitbake. There is some
basic documentation here:
http://gumstix.org/software-development/open-embedded.html.
However, if you post back about what specific source code you wish to
change, the community will likely have some good suggestion on how
best to handle that particular case.
Vague answer---sorry---it is just a lot to explain in one go!
-Ash
On Thu, Jun 23, 2011 at 6:38 PM, JamesAng <angweiyang@...> wrote:
>
> Hi Ash,
>
> Thanks for the suggestion for my 2 issues.
>
> As I'm a newbie to Linux world thus I follows closely the wiki guides to
> setup my development machine on Ubuntu 10.04 LTS (
> http://www.gumstix.org/software-development/open-embedded/61-using-the-open-embedded-build-system.html
> http://www.gumstix.org/software-development/open-embedded/61-using-the-open-embedded-build-system.html
> ) and appreciate all the help that I can get from the community.
>
> I understand that I've to make changes to the source files to overcome some
> of the issues I encountered with the touchscreen. But, I don't know where
> are the source files located in my development machine to make the changes
> so that it will be pickup and compile using the 'bitbake
> omap3-desktop-nand-image' command.
>
> The following are the directories in my overo-oe folder:
> bitbake
> org.openembedded.dev
> build
> sources
> tmp
>
> Can you tell me where I should modify these driver's files so that it can be
> bitbake?
> or did I missed cloning some source's repository?
>
> Thks a million in adv. :)
>
> James.
>
>
>
> Ash Charles-2 wrote:
>>
>> Hi James,
>>
>> You've mentioned two issues:
>> - vertical flip of display: this seems to be an issue in the April15th
>> image. We are looking in to a fix but for the time being, switching
>> to a different image or changing the version of Xorg would be my
>> suggestion.
>> - low touchscreen sensitivity. As discussed in this thread, there are
>> several software work-arounds all of which effectively change the
>> frequency of the LCD clock. Sorry I don't have more details here but
>> this particular problem seems real but is hard to replicate.
>>
>> Thanks for providing the details about the inductor---this helps us
>> isolate any hardware issues.
>>
>> -Ash
>> On Wed, Jun 22, 2011 at 6:48 PM, JamesAng <angweiyang@...> wrote:
>>>
>>> Hi Ash,
>>>
>>> I'm using the Chestnut board & I experience the same issue.
>>>
>>> For the L2 inductor on my board, it's a 3mm(W)x4mm(L)x~2mm(H) black box
>>> with
>>> no surface-marking.
>>> The surrounding of the inductor is concaved.
>>>
>>> My board is PCB30005-R2467 & bought recently about a month ago.
>>>
>>> Please advise.
>>>
>>> Thanks in adv.
>>>
>>> James.
>>>
>>>
>>> Ash Charles-2 wrote:
>>>>
>>>> Hi Brent,
>>>>
>>>> Thanks for the update. I wonder that you are seeing electrical
>>>> interference between the backlight circuitry and the touchscreen ADC
>>>> sampling---this sounds increasingly like a hardware issue.
>>>>
>>>> Can you take a photo or describe inductor L2 on the Chestnut board? As
>>>> noted here
>>>> (http://pubs.gumstix.com/boards/CHESTNUT/PCB30005-2467/Readme.txt),
>>>> the part has been changed so I'd like to determine which you have.
>>>>
>>>> -Ash
>>>>
>>>> On Sat, Jan 29, 2011 at 1:03 PM, BrentP <brent.perteet@...> wrote:
>>>>>
>>>>> I confirmed yesterday that my touchscreen responsiveness was directly
>>>>> related
>>>>> to the pixel clock setting of the LCD. I still don't understand why,
>>>>> but
>>>>> if
>>>>> I set the pixel clock to 9.6MHz (the nominal clock in the datasheet of
>>>>> the
>>>>> LCD), the touchscreen response was sluggish. As I increased it, it
>>>>> became
>>>>> better and better. I currently have it set to 15Mhz which is the top
>>>>> end
>>>>> spec'd in the datasheet. I had it as higha s 23.5MHz and everything
>>>>> was
>>>>> still working well.
>>>>>
>>>>> Any clues as to why the pixel clock on the LCD would effect things like
>>>>> this?
>>>>>
>>>>> Brent
>>>>>
>>>>>
>>>>>
>>>>> BrentP wrote:
>>>>>>
>>>>>> The fact that setting defaultdisplay to dvi was a clue and got me to
>>>>>> looking closer. If I set to dvi and use fbset to set the resolution
>>>>>> to
>>>>>> 480x272, I get output to the lcd that is mostly correct - there is a
>>>>>> white
>>>>>> stripe on the right hand side, but otherwise the video looks correct.
>>>>>> In
>>>>>> this mode, running ts_test works as expected. The touchscreen is very
>>>>>> responsive.
>>>>>>
>>>>>> I dug into which video driver was being used when setting
>>>>>> defaultdisplay
>>>>>> to lcd43 vs. dvi.
>>>>>>
>>>>>> Long story short, lcd43 uses driver "samsung_lte_panel" (which is for
>>>>>> Samsung SAMSUNG_LTE430WQ) and dvi uses "generic_panel." The 4.3"
>>>>>> display
>>>>>> I have that I bought from Gumstix is an LG/Philips LB043WQ2. The
>>>>>> Samsung
>>>>>> driver sets the pixel clock to 9200. When in "dvi" mode the clock is
>>>>>> at
>>>>>> 42553 (according to the output of fbset).
>>>>>>
>>>>>> I'm messing around to get the right timing settings for fbset to
>>>>>> output
>>>>>> the full resolution to my display to see if it is indeed just the LCD
>>>>>> driver used. It seems strange to me that this would be the cause of
>>>>>> the
>>>>>> slow touchscreen response, but I'm not terribly familiar with the way
>>>>>> things happen in the kernel.
>>>>>>
>>>>>> Brent
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Ash Charles [mailto:ashcharles@...]
>>>>>> Sent: Friday, January 28, 2011 12:33 PM
>>>>>> To: General mailing list for gumstix users.
>>>>>> Subject: Re: [Gumstix-users] LCD touch screen unusable on
>>>>>> Overo/Chestnut
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I haven't seen this behaviour but these symptoms seemed bizarre and
>>>>>> got me wondering.
>>>>>>
>>>>>> I'm just thinking aloud here:
>>>>>> * is this a hardware or a software issue? If it is a hardware issue
>>>>>> due to noise or settling time, is there a software workaround just by
>>>>>> running at a different clock rate?
>>>>>> * the driver for the touchscreen is found in
>>>>>> drivers/input/touchscreen/ads7846.c and there is a TS_POLL_PERIOD
>>>>>> parameter that, by varying, might show whether this is a software
>>>>>> resource contention issue.
>>>>>> * notably, the touchscreen driver uses the input subsystem, the spi
>>>>>> bus, interrupts, and a high-resolution timer. Based on the symptoms,
>>>>>> there is no resource contention in the input subsystem (USB is fine).
>>>>>> Interrupts?
>>>>>> * app note sbaa036 explains the possible electrical interference
>>>>>> problems due to LCD backlight circuits. The backlight circuit and the
>>>>>> ADS chip are physically distant in the board layout for the Chestnut43
>>>>>> and some of the interference reduction recommendations are followed
>>>>>> but perhaps more filtering is required.
>>>>>> * do changing the ads7846_config parameters in arch/arm/board_overo.c
>>>>>> have any effect?
>>>>>> * does changing the PWM signal supplied to the LCD backlight change
>>>>>> the performance of the touchscreen. This is possible using Scott
>>>>>> Ellis's PWM module (https://github.com/scottellis/omap3-pwm)
>>>>>>
>>>>>> -Ash
>>>>>>
>>>>>> On Fri, Jan 28, 2011 at 8:26 AM, BrentP <brent.perteet@...>
>>>>>> wrote:
>>>>>>>
>>>>>>> If I set the defaultdisplay to dvi in u-boot, i consistent see fast
>>>>>>> results
>>>>>>> from the output of ts_print almost 100 samples per second). If I set
>>>>>>> the
>>>>>>> defaultdisplay to lcd43 the output is closer to 5 samples per second
>>>>>>> on
>>>>>>> average.
>>>>>>>
>>>>>>> I don't know why there is this interaction and I have no idea how to
>>>>>>> fix
>>>>>>> it.
>>>>>>>
>>>>>>> Have you had any breakthroughs, Derek?
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> BrentP wrote:
>>>>>>>>
>>>>>>>> I'm having precisely the same issue. I've seen it on prebuilt images
>>>>>>>> and
>>>>>>>> ones I've bitbaked. Right now I'm running the omap3-console-image
>>>>>>>> which
>>>>>>>> boots to a login prompt to the LCD.
>>>>>>>>
>>>>>>>> I noticed a clue this morning. When the local console blanks (the
>>>>>>>> LCD)
>>>>>>>> I
>>>>>>>> notice that the output from ts_test is *much* faster, as low as 5 ms
>>>>>>>> between samples (the poll rate to the ADS7846). If the console is
>>>>>>>> not
>>>>>>>> blanked, and I use ts_test to test the touchscreen, the time between
>>>>>>>> samples is slow, up to 500ms between samples.
>>>>>>>>
>>>>>>>> If I use a USB mouse as input, the motion is very smooth in both X
>>>>>>>> Windows
>>>>>>>> and a Qt Embedded app.
>>>>>>>>
>>>>>>>> There seems to be some interaction between drawing to the
>>>>>>>> framebuffer
>>>>>>>> and
>>>>>>>> the touchscreen driver.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Derek Baum wrote:
>>>>>>>>>
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> We have several gumstix overo with chestnut expansion board and LCD
>>>>>>>>> touch
>>>>>>>>> screen.
>>>>>>>>>
>>>>>>>>> They boot OK and display the default desktop, but the touch screen
>>>>>>>>> is
>>>>>>>>> virtually unusable.
>>>>>>>>>
>>>>>>>>> It is even a challenge to run the calibration utility (forced by
>>>>>>>>> removing
>>>>>>>>> /etc/pointercal). I had to resort to using one of the gumstix
>>>>>>>>> aerials
>>>>>>>>> as
>>>>>>>>> a
>>>>>>>>> stylus, as the touch screen would not accept any of my finger
>>>>>>>>> presses.
>>>>>>>>>
>>>>>>>>> We are using a pre-built image from October 2010:
>>>>>>>>>
>>>>>>>>> $ uname -a
>>>>>>>>> Linux gumstix1 2.6.34 #1 Wed Oct 13 12:00:38 PDT 2010 armv7l
>>>>>>>>> GNU/Linux
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Overo # printenv
>>>>>>>>> dvimode=1024x768MR-16@...
>>>>>>>>> defaultdisplay=lcd43
>>>>>>>>>
>>>>>>>>> How can I fix this?
>>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>>
>>>>>>>>> Derek
>>>>>>>>>
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>>>>>>>>> _______________________________________________
>>>>>>>>> gumstix-users mailing list
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>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> View this message in context:
>>>>>>> http://old.nabble.com/LCD-touch-screen-unusable-on-Overo-Chestnut-tp30728009p30788570.html
>>>>>>> Sent from the Gumstix mailing list archive at Nabble.com.
>>>>>>>
>>>>>>>
>>>>>>> ------------------------------------------------------------------------------
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>>>>>>> _______________________________________________
>>>>>>> gumstix-users mailing list
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>>>>>>>
>>>>>>
>>>>>> ------------------------------------------------------------------------------
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>>>>>> _______________________________________________
>>>>>> gumstix-users mailing list
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>>>>>> ------------------------------------------------------------------------------
>>>>>> Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)!
>>>>>> Finally, a world-class log management solution at an even better
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>>>>>> _______________________________________________
>>>>>> gumstix-users mailing list
>>>>>> gumstix-users@...
>>>>>> https://lists.sourceforge.net/lists/listinfo/gumstix-users
>>>>>>
>>>>>>
>>>>>
>>>>> --
>>>>> View this message in context:
>>>>> http://old.nabble.com/LCD-touch-screen-unusable-on-Overo-Chestnut-tp30728009p30796698.html
>>>>> Sent from the Gumstix mailing list archive at Nabble.com.
>>>>>
>>>>>
>>>>> ------------------------------------------------------------------------------
>>>>> Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)!
>>>>> Finally, a world-class log management solution at an even better
>>>>> price-free!
>>>>> Download using promo code Free_Logger_4_Dev2Dev. Offer expires
>>>>> February 28th, so secure your free ArcSight Logger TODAY!
>>>>> http://p.sf.net/sfu/arcsight-sfd2d
>>>>> _______________________________________________
>>>>> gumstix-users mailing list
>>>>> gumstix-users@...
>>>>> https://lists.sourceforge.net/lists/listinfo/gumstix-users
>>>>>
>>>>
>>>> ------------------------------------------------------------------------------
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>>>> Finally, a world-class log management solution at an even better
>>>> price-free!
>>>> Download using promo code Free_Logger_4_Dev2Dev. Offer expires
>>>> February 28th, so secure your free ArcSight Logger TODAY!
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>>>> _______________________________________________
>>>> gumstix-users mailing list
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>>>> https://lists.sourceforge.net/lists/listinfo/gumstix-users
>>>>
>>>>
>>>
>>> --
>>> View this message in context:
>>> http://old.nabble.com/LCD-touch-screen-unusable-on-Overo-Chestnut-tp30728009p31908184.html
>>> Sent from the Gumstix mailing list archive at Nabble.com.
>>>
>>>
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>>
>> ------------------------------------------------------------------------------
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>
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> Sent from the Gumstix mailing list archive at Nabble.com.
>
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